On the Fabrication of Solar Cells Based on Newly Produced Recycled Silicon Feedstocks From CABRISS - A Comparative Study Between Material Properties and Solar Cell Performances

Abstract

Second life silicon solar cells based on 100% recycled silicon have been recently produced at CEA-INES in the frame of the CABRISS Project. A maximum efficiency of 18.1% has been reached (Al-BSF solar cells), with Mono-like silicon substrate grown from recycled feedstock. During this first period of the project, several Silicon ingots were produced using different conventional methods: Multi-Si standard casting method, Standard Cz-Si pulling and also mono-Si seed-assisted casting method (Mono-like technology). To assess the photovoltaic potential of recycled materials, we developed an overall material qualification protocol to evaluate the effect of the different solar cell processing steps on the material quality. This study shows that all solar cells performances are in good agreement with the data extracted from this protocol, especially with the bulk carrier lifetime determined after each technological step. In addition this study brings new insights into the compatibility between novel Recycled Silicon feedstocks (Re-Si) and the fabrication of standard solar cells. This is definitely an important step to improve the definition of the future Re-Si feedstocks specifications and enhance the development of efficient recycling processes.

Second life silicon solar cells based on 100% recycled silicon have been recently produced at CEA-INES in the frame of the CABRISS Project. A maximum efficiency of 18.1% has been reached (Al-BSF solar cells), with Mono-like silicon substrate grown from recycled feedstock. During this first period of the project, several Silicon ingots were produced using different conventional methods: Multi-Si standard casting method, Standard Cz-Si pulling and also mono-Si seed-assisted casting method (Mono-like technology). To assess the photovoltaic potential of recycled materials, we developed an overall material qualification protocol to evaluate the effect of the different solar cell processing steps on the material quality. This study shows that all solar cells performances are in good agreement with the data extracted from this protocol, especially with the bulk carrier lifetime determined after each technological step. In addition this study brings new insights into the compatibility between novel Recycled Silicon feedstocks (Re-Si) and the fabrication of standard solar cells. This is definitely an important step to improve the definition of the future Re-Si feedstocks specifications and enhance the development of efficient recycling processes.